1. Field of the Invention
The present invention relates to a method, apparatus, and medium for transforming a graphic data of an object and a computer readable recording medium storing a program for executing the method.
2. Description of the Related Art
FIGS. 1A through 1C are diagrams for explaining a level of detail (LOD) of an object. There conical shapes are shown in FIG. 1A. The leftmost conical shape is not substantially a cone rather, it approximates a pyramid shape having 4 planes. The center conical shape has 8 planes and the rightmost conical shape has 16 planes. The three conical shapes shown in FIG. 1A are different from one another according to a direction in which light is reflected from each of the three conical shapes.
FIG. 1B illustrates the three conical shapes of FIG. 1 viewed from a farther distance. The leftmost conical shape can be distinguished from the rightmost conical shape and the center conical shape. However, it is difficult to clearly identify a difference between the rightmost conical shape and the center conical shape.
FIG. 1C illustrates the three conical shapes of FIG. 1 viewed from a much farther distance. In this case is almost impossible to identify a difference among the three conical shapes.
Such image sequences prove that it is more difficult to identify the details of an object as the distance between the object and a viewer increases. This indicates that not all details of the object need to be drawn when the object is seen from a large distance. When the shape of an object becomes more complicated, more tasks are needed to draw the object. Thus, it is not necessary to draw in detail the object when a viewer is far away from it.
Three-dimensional data is too large to be effectively rendered with limited resources. Accordingly, progressive rendering, which takes a user's placement into consideration, is desired.